The invention relates to a coffee machine.
Coffee machines in the prior art operate according to different principles. The most common models are the so-called pressureless coffee machines. In these water flows from a storage container into an electrically heatable pipe. Particularly as a result of the evolution of steam in this pipe, heated water is then pushed through a riser to an outlet via which the heated water then drips into a coffee filter. The filter coffee can then flow from this coffee filter at atmospheric pressure into a pot.
In contrast, in espresso machines an elevated pressure prevails in the area of the coffee grounds, for example 15 bar. This is achieved by supplying water from a water container or another water supply to an electric-motor-driven pump which then supplies the water at high pressure via an electrically heatable area to a coffee grounds receiving device. This coffee grounds receiving device generally comprises a filter for receiving the coffee. In order to generate the high pressure in the coffee area, during operation the coffee grounds receiving device is located in an area which is sealed towards the atmosphere, which can be designated as a pressure chamber or brewing chamber.
In another coffee machine which operates on a different principle, it is provided to first transfer the water for preparing the coffee from a water container into a heatable intermediate container. From this intermediate container the heated water is passed to an electric-motor-driven pump from which it is supplied at elevated pressure, for example 2 to 3 bar, to a coffee grounds receiving device. In this case, it is provided that unlike in the espresso machine the coffee is not introduced into the coffee grounds receiving device in loose form as coffee grounds but is inserted in a retainer in the form of a coffee pad, that is, in compacted form surrounded by filter paper. The retainer with a retainer cover via which water is supplied can form a sealed pressure chamber. At the same time, the retainer for the coffee pads is allocated a plurality of functions. Firstly, the retainer provides a sealing surface so that a pressure chamber can be formed. Moreover, the retainer has an outlet opening from which the coffee can emerge. Furthermore, the coffee pad should be mounted in the retainer in a manner such that flow through the coffee pad is not impeded. Such a coffee machine occupies an intermediate position between a conventional pressureless coffee machine and an espresso machine.
WO 01/15582 A1 relates to a coffee machine to which the coffee grounds are supplied in the form of coffee pads. The coffee pads are inserted in a lower portion of the brewing chamber and the upper portion of the brewing chamber can be folded onto the lower portion by the user by means of a hinge, wherein an engaging connection between the two housing portions which are hinged relative to one another ensures sealing of the brewing chamber. A problem with this system is that after the brewing process the coffee pad can stick to the upper portion of the brewing chamber when opening the coffee machine. Another problem can arise if the coffee machine is actuated when opened since hot water can then spray in the direction of the user of the coffee machine.
Known from EP 1 050 258 A1 is a coffee machine wherein coffee pads are inserted in a pulled-out drawer and are then brought into the brewing position by pushing in the drawer. For sealing the brewing chamber, a brewing chamber upper portion is automatically moved over the coffee pad from above before the brewing process. After the brewing process, the coffee pads are automatically removed inside the coffee machine in a collecting container. Particularly as a result of the motor-driven components of the coffee machine, this is very complex and therefore expensive to produce.